Effects of Varieties, Fertilization Methods and Transplanting Time on Yielding Ability in Rice – Analysis with a Rice Variety ‘Niji-no-kirameki’ –

Abstract

To attain both high yield and superior grain quality in rice cultivation, I compared the yielding abilities of ‘Niji-no-kirameki’, a new high yielding rice variety with superior appearance quality and those of an elite rice variety ‘Koshihikari’ under the conditions of early, standard, and no topdressing in normal and late transplanting for two years in the North Kanto area of Japan. ‘Niji-no-kirameki’ had a slightly larger sink size due to the much heavier thousand grain weight compared to ‘Koshihikari’ although top dry weight at the full heading stage was similar in the two varieties. The total spikelet number per unit area (TSN) was smaller in ‘Niji-no-kirameki’. ‘Niji-no-kirameki’ had a higher percentage of ripened grain (PRG) in spite of the slightly larger sink size, resulting in a much higher yield. This might be related to the longer filling duration in ‘Niji-no-kirameki’. Topdressing considerably increased the yield. The yield was slightly higher with standard topdressing than with early topdressing. The high yield obtained by both early and standard topdressing could be attributed to the large sink size and to the high leaf color value during the grain filling period particularly with standard topdressing. Late transplanting resulted in a much larger TSN, much lower PRG and similar yield in 2020 and smaller TSN, lower PRC and much lower yield in 2021 compared to normal transplanting.